Apparatus and method for continuously casting of material, especially ferrous material



Oct. 22, 1968 3 DUFLOT ET AL 3,406,737

APPARATUS AND METHOD FOR CONTINUOUSLY CASTING 0F MATERIAL, ESPECIALLY FERROUS MATERIAL Filed March 4, 1966 NQ n v y mi n w \w -H WF Wm m y n m M HMHHl I 7M United States Patent 3,406,737 APPARATUS AND METHOD FOR CONTINUOUS- LY CASTING OF MATERIAL, ESPECIALLY FER- ROUS MATERIAL Jean Dufiot and Pierre Vayssiere, Metz, France, assignors to Institut de Recherches de la Siderurgie Fraucaise Saint Germaiu-en-Laye, Seine-et-Oise, France Filed Mar. 4, 1966, Ser. No. 531,913 Claims priority, application France, Mar. 3, 1965, 8,303; Jan. 6, 1966, 44,984 13 Claims. (Cl. 16486) ABSTRACT OF THE DISCLOSURE A continuous casting process, especially for casting ferrous material, in which an elongated circumferentially closed envelope is continuously formed from a material adapted to absorb a certain amount of heat, in which the envelope has an outer layer which decomposes under the influence of heat and an inner layer of metal powder, and in which the material to be cast is continuously poured in hot molten state into the interior of the envelope while the latter with the material therein is continuously moved in the desired direction; and an apparatus for carrying out the process.

The present invention relates to a method and apparatus for continuously casting of material, especially ferrous material.

It is an object of the present invention to provide for a method and apparatus for continuously casting material, especially ferrous material, to produce a continuous casting of predetermined shape.

It is an additional object of the present invention to provide for a method and apparatus for continuously casting of material, especially ferrous material, which does not require a permanent mold for receiving the cast material therein.

With these objects in view, the process according to the present invention for continuously casting material, especially ferrous material, mainly comprises the steps of continuously forming an elongated envelope, continuously discharging a material to be cast in liquid form into the interior of the envelope as the latter is formed, and continuously moving the envelope and the material therein in a desired direction. Preferably the process includes further the step of continuously cooling the envelope while the same is moved in the aforementioned direction.

The envelope may be formed by guiding at least two flexible bands toward each other and pressing opposite edge portions of the band against each other with opposite face portion of the bands between the edge Portions spaced from each other.

The flexible bands may be in the form of flexible metal bands and the method may include the further step of guiding the metal bands in close contact with the metal cast into the envelope formed by the metal bands so that the metal bands will fuse with the cast material to form a unitary member. The metal bands, especially if the material to be cast is steel, may be formed from stainless steel so that the metal bands when united with the cast steel form an inoxidizable outer surface of the final product.

On the other hand, the bands may be formed from material which decomposes under the influence of the heat of the material cast into the envelope and in this case the method according to the present invention includes the further step of covering at least the opposite face portions of the band which come into contact with the 'cast metal with a layer of metal prior to the formation of the envelope from the bands. The layer of metal on the bands may be formed by first covering the face portions of the band with adhesive material and subsequently thereto applying metal powder onto the adhesive so as to form a continuous metal layer on the bands. The bands may also be covered with a layer of material adapted to react with the metal cast in the envelope so as to obtain desired surface characteristics on the finished product.

According to the present invention the elongated envelope may also be guided between members of predetermined shape and contour so as to form a finished product of desired cross section corresponding to the contour of the members engaging the outer surfaces of the envelope.

The apparatus for continuously casting material, especially ferrous material, mainly comprises a container having an inlet opening for feeding hot liquid material to be cast into the container and an outlet opening so that the material fed into the container will be discharged in a continuous stream from the outlet opening, means for continuously forming a consumable envelope aligned with a stream of material discharged from the outlet opening so that the material discharged will be received in and fill the envelope, and means for guiding and moving the envelope with the material received therein in a predetermined direction. The apparatus preferably includes also means for cooling the envelope during movement thereof.

The means for continuously forming the aforementioned envelope include roller means for continuously feeding at least one hand of flexible material forming at least part of the envelope. Preferably, the means for continuously forming the aforementioned envelope include at least two roller means constructed and arranged to press opposite edge portions of at least two bands against each other while leaving face portions of the bands between said edge portions spaced from each other so as to continuously form an elongated space in which the cast material will be received. The means for guiding and moving the envelope include at least two driven rollers and two guide rollers arranged to engage opposite outer surface portions of the envelope. The means for cooling the aforementioned envelope preferably include means for directing jets of cooling fluid against the outer surface of the envelope.

The envelope is in form of an elongated sheath which is formed before or during the contact with the material to be cast and which cannot be reused again, and which also may be termed a consumable envelope, in fact, if the envelope is formed from metal, this metal envelope is combined with or fused to the metal poured into the envelope and forms the skin of the final product, whereas if the envelope is formed from material which decomposes under the influence of the heat of the molten metal poured into the envelope, the envelope will disappear during the process.

Broadly speaking, the process according to the present invention comprises the step of continuously forming an elongated envelope in the interior of which one continuously pours metal in liquid form which upon contact with the envelope forms a solid outer shell which is further cooled by means known in the art. To this effect one continuously pours the metal emanating from a channel into an elongated envelope adapted to absorb a certain quantity of heat suflicient to form a shell of solid metal. For this purpose one may use an envelope formed from metal bands capable of absorbing a quantity of heat suflicient so that the liquid metal solidifies nearly instantaneously upon contact with the envelope.

On the other hand, it is also possible to use envelopes formed from bands decomposable by the heat of the liquid metal and bands from carton and textiles have been used. In this case one covers the surface portions of the envelope which come in contact with the metal to be cast with a layer of powdered metal, and heating of this layer absorbs sutficient calories to form a thin skin of solid metal constituted in part from the powdered metal which combines with the base metal poured into the interior of the envelope. The powdered metal may be of the same composition as the base metal to be-cast or the powder may be of a different composition. In the latter case, by using a powder of ferromanganese, one has succeeded in obtaining a considerable increase in the surface hardness of the base metal. For the same purpose one can also use silicon carbide or carbon. One can also use a layer of pulverulent sulfur or iron sulfide for covering the surface portion of the bands which come in cont-act with the cast metal in order to facilitate free-cutting or one can cover the surface portions of the envelope with powdered chrome or nickel which will provide on the cast metal ananticorrosive skin. An advantage of the process according to the present invention consists in the use of the aforementioned consumable envelope.

As mentioned above two diiferent types of consumable envelopes may be used. A first type of envelope is constituted by bands of material which is decomposable by heat, such as for instance carton or textile material, and which upon contact with the cast liquid metal partially decomposes and becomes gradually detached from the solidifying product, which detachment is produced by jets of cooling liquid or cooling gas. The second type of envelopes is constituted by metallic bands which are, contrary to the envelopes of carton or textile material, not decomposed but are integrated into the cast metal and form the outer skin of the cast product. Of special advantage is the use of an envelope of a layer of stainless steel while the metal cast in the envelope is ordinary steel, for instance steel obtained from a Thomas converter. If the product thus obtained is subsequently subjected to a rolling operation, the surface quality of the final product will be that of the metallic envelope. If the product produced is flat, one can, after rolling the product to a small thickness, utilize it again to produce an envelope in a following fabrication step while conserving a constant surface quality.

According to the present invention rollers rotating in opposite directions relative to each other are used forming the envelope and in the space between the rollers different forms may be obtained, for instance the rollers may be flat, concave or be formed with different grooves. The envelope formed by pressing the edge portions of two bands against each other by the extremities of the two rollers is filled with metal and the pressure of the metal applies the envelope against the surface portions of the rollers between the extremities thereof so that the metal will obtain a well defined form. In this way all desired forms may be obtained and even profiles which are difiicult to obtain with means known in the art.

To start the process according to the present invention is simple. At the start of the casting process it is sufficient to close the envelope at its lower end and to fill the closed end with a cooling material, for instance powdered metal and to subsequently guide the envelope along a path along which the cast metal bar is to be formed. If the envelope is made from textile or carton the lower end of the elongated envelope is sewn together or clasped together, if the envelope is formed from a metal one closes the lower end of the envelope by crimping or welding the lower extremities of the bands forming the envelope to each other.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific em- 4 bodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a schematic vertical cross-section illustrating the apparatus of the present invention; and

FIG. 2 is a horizontal cross-section showing two rollers pressing edge "portion of two bands forming the envelope according to the present invention against each other.

, Referring now to the drawings, it will be seen thatthe apparatus according to the,present-invention comprises a bath of liquid metal 1 continuously replenished by means not shown in the drawing and flowing out from the container through an outlet opening 2 at the bottom thereof so as to pass in a continuous stream through guide or shield means 3.

The apparatus comprises further two bands 4 and 4a, which may for instance heformed .from carton, and which are taken ofi from supply spools Sand 5a by two pairs of driven rollers 9, 10 and 9a, 1011 respectively. Adhesive applying means 6 and 6a are arranged respectively between the bobbins 5 and 5a and the aforementioned drive rollers which apply to the upper surfaces of the hands a layer of adhesive and the upper surfaces of the bands to which a layer of adhesive is applied are respectively guided beneath funnels 7 and 7a containing a powdered material, for instance powdered metal, which is applied to the adhesive layers so as to form on the latter layers of powdered metal 8 and 8a. The powdered metal layer is pressed against the upper surfaces of the bands 4 and 4a as the latter pass through the driven pairs of rolls 9, 10 and 9a, 10a, respectively and subsequently the bands are passed over the rollers 11 and 11a which may have a form as shown in FIG. 2 so as to press the edge portions of the bands 4 and 4a against each other to form an elongated envelope united 'at the lateral portions 20 and 21 to each other, whereas the face portions between the connected end portions are spaced from each other so that the liquid metal emanating from the shield means 3 will be received in the envelope, whereby the pressure of the metal presses the spaced portions of the envelope against the surfaces of the rotating rollers 11 and 11a. 1 i v The surfaces of the rollers 11 and 11a which are not in contact with the bands 4 and 4a are cooled by jets of cooling fluid 12 and 12a, as schematically indicated in FIG. 1. The liquid metal emanating from the shield means 3 passes into the envelope the inner surfaces of which are covered with powdered metal and the cooling thus obtained is so intense that the-outer layer of the cast liquid metal, which fuses with the powdered metal, is solidified so that one can further cool the outer layer by jets of water 13 and 13a, 14 and 14a, 15 and 15a, which also strip the carton envelope, which is charred by the heat, from the solidified outer layer. The ingot thus formed, comprising the outer solidified shell 16 and the still liquid interior part 16a, is guided by pairs of rollers 17 and 17a, 18 and 18a, and 19 and 19a to a place of further use. At least one pair of the rollers is driven by means not shown in the drawing.

FIG. 2 shows a top view'of the two rollers 11 and 11a drawn to a larger scale. These rollers press the edge portions 20 and 21 of the two bands 4 and 4a against each other. The layers 8 and 8a of powdered metal are not shown any longer in FIG. 2 because these layers form part of the solidified metal shell 16 confining the still liquid portion 16a in the interior of the ingot. It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of continuous casting apparatus 'differing from thetypes described above. I

For instance the bands constituting the envelopes may also be covered by other materials, which may be solid.

or liquid, for instance by metal carbonyls, and of course the bands may also be formed from metal, for instance steel or stainless steel. I I

While the invention has been illustrated and described as embodied in apparatus for continuously casting of metals in which the liquid metal is cast into an elongated envelope while the latter is formed, it is not intended to be limited to the details shown, since various modifications and structural changes may be made Without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A continuous casting process comprising the steps of continuously forming an elongated circumferentially closed envelope of material adapted to absorb a certain amount of heat and having an outer layer which decomposes under the influence of heat and an inner layer of metal powder; continuously discharging material to be cast in hot molten state into the interior of the envelope as the latter is formed; and continuously moving the envelope and the material therein in a desired direction.

2. A process as set forth in claim 1, wherein the material to be cast is of metal, and wherein said metal powder is of the same nature as the metal to be cast.

3. A process as set forth in claim 1, wherein said metal powder contains substances modifying the surface characteristics of the product produced by the casting process.

4. A continuous casting process as set forth in claim 1, and including the step of cooling the envelope during moving the same and the material therein in said desired direction.

5. A method as set forth in claim 4, wherein said envelope is formed by guiding at least two flexible bands toward each other and pressing edge portions of said bands against each other with opposite face portions of said bands between said edge portions spaced from each other.

6. A method as set forth in claim 5, and including the step of first covering said face portions of the band with adhesive material and subsequently applying the metal powder onto the adhesive material.

7. A process as set forth in claim 5, wherein said inner layer of metal powder is applied to said flexible bands prior to the formation of the envelope from the bands.

8. A process as set forth in claim 7, wherein said metal powder is adapted to react with material cast into the envelope to change the surface characteristics of the prodnot produced by the casting process.

9. A continuous casting apparatus comprising at least two roller means for continuously forming an elongated circumferentially closed envelope from sheet material adapted to absorb a certain amount of heat and having an outer layer which decomposes under the influence of heat and an inner layer of metal powder, said elongated envelope having at least one open end; means for discharging a continuous stream of material to be cast into said open end of said envelope; and means for guiding and moving said envelope with the material therein in a predetermined direction.

10. An apparatus as set forth in claim 9, and including means for cooling said envelope during the movement thereof.

11. An apparatus as set forth in claim 10, wherein said at least two roller means are constructed and arranged to press opposite edge portions of at least two bands against each other while leaving face portions of said bands between said edge portions spaced from each other.

12. An apparatus as set forth in claim 10, wherein said means for cooling said envelope comprise means for directing jets of cooling fluid against the outer surface of said envelope.

13. An apparatus as set forth in claim 9, further comprising, upstream of said roller means, means for applying adhesive material to said face portions of said bands; and means between said adhesive material applying means and said roller means for applying metal powder to said face portions covered with adhesive material.

References Cited UNITED STATES PATENTS 2,055,980 9/1936 Liebmann 16486 2,128,943 9/ 1938 Hudson 164-86 2,174,733 10/1939 Chace 164-75 XR 2,692,411 10/1954 Brennan 164--86 XR 3,123,856 3/1964 Dye et al. 184 3,163,896 1/1965 Rochester et al. 164278 XR 3,240,846 3/1966 Voelker 18-4 3,276,082 10/ 1966 Thomas 16475 XR 3,343,590 9/1967 Radd 16487 FOREIGN PATENTS 742,180 11/1943 Germany.

491,341 8/1938 Great Britain.

203,489 6/ 1939 Switzerland.

228,380 11/1943 Switzerland.

J. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner. 

